Re: Experimental data as function?

*To*: mathgroup at smc.vnet.net*Subject*: [mg25766] Re: Experimental data as function?*From*: "Allan Hayes" <hay at haystack.demon.co.uk>*Date*: Sat, 21 Oct 2000 18:33:01 -0400 (EDT)*References*: <8ssqbe$19n@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Eric, Make an interpolating function: data = Table[{x, Sin[x]}, {x, 0, 2Pi, Pi/50}]; sin = Interpolation[data] InterpolatingFunction[{{0, 2 Pi}}, <>] NIntegrate[sin[x], {x, 0, 2.57}] (*don't use Integrate*) 1.84104 NIntegrate[Sin[x], {x, 0, 2.57}] 1.84104 Plot[{sin[x], sin'[x]}, {x, 0, 2Pi}] -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565 "Eric Sommer" <erso at hrem.mpi-stuttgart.mpg.de> wrote in message news:8ssqbe$19n at smc.vnet.net... > Hi, > > I have measured an experimental curve and the data are available as > (x,y=f(x)) ASCII data pairs. I would like to use this curve as a > function that I can insert, for example, in calculations, or that I can > integrate. It should work in the way that for a given x, the measured y > value will be taken. > I found methods to import data as lists, but could not find any hint to > use them as a function. > > Is there a possibility to create such a function with Mathematica? How > can it be done? What will happen, e.g. for an integration, when x values > appear that were not measured? > > Thank you, > Eric Sommer >